IMPROVED PERMEABILITY PREDICTION IN HETEROGENEOUS CARBONATE RESERVOIRS: A NEW APPROACH USING ROCK TYPING AND WIRELINE FORMATION TESTING

摘要

Carbonate rocks are a synonym for heterogeneity.Attempts to characterize carbonate reservoirs followvarious rock typing routes in order to predict saturationand permeability. The rock typing methods focusmainly on Special Core Analysis output where corederived permeability and capillary pressures play acentral role. Given the late stage in a typical projectwhere these results become available, a full integrationwith larger volume sampling methods (such as wirelineformation testing, and well testing) is usually notbrought to a closure. For a heterogeneous formation weattempt to bring this information in agreement andhighlight differences between the results of differentsampling methods. More specifically, we focus on theagreement between various permeability scales toaccurately model our reservoir.Also, we will show that by using fluid mobility datafrom wireline formation testing pressure measurementsone can improve the accuracy of rock –typing predictedpermeability by comparing mobility against thepredicted permeability obtained via various averagingmethods. In addition, a new method of QCing andensuring consistency between static and dynamicmodels will be presented. In populating a reservoirmodel, the permeability and saturation are typicallyforward modeled in parallel streams without aconsistency check between these parameters. Wherecore permeability is not available we will show that apermeability curve can be derived based on input dataalready available in the model: via capillary pressures.The advantage of this method is that it can be calibrateddirectly to well performance.